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[v2,0/4] reset: gpio: ASoC: shared GPIO resets

Message ID 20240105155918.279657-1-krzysztof.kozlowski@linaro.org
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Series reset: gpio: ASoC: shared GPIO resets | expand

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Krzysztof Kozlowski Jan. 5, 2024, 3:59 p.m. UTC 
Hi,

Changes in v2
=============
1. wsa884x.c: add missing return in wsa884x_get_reset(), correct comment.
2. qcom,wsa8840.yaml: fix oneOf syntax.
3. reset/core.c:
   - Revise approach based on Bartosz comments: parse the reset-gpios phandle
     with arguments, do not use deprecated API and do not rely on gpio_desc
     pointer.
   - Create a list of instantiated platform devices to avoid any duplicates.
   - After creating reset-gpio platform device, try to get new reset controller
     or return EPROBE_DEFER.
   - Drop the "cookie" member and add new "of_args" to "struct
     reset_controller_dev".
4. reset-gpio.c:
   - Fix smatch warning on platdata evaluation.
   - Parse GPIO args and store them in rc.of_args.

Description
===========

We have at least few cases where hardware engineers decided to use one
powerdown/shutdown/reset GPIO line for multiple devices:

1. WSA884x (this and previous patch):
https://lore.kernel.org/all/b7aeda24-d638-45b7-8e30-80d287f498f8@sirena.org.uk/
2. https://lore.kernel.org/all/20231027033104.1348921-1-chris.packham@alliedtelesis.co.nz/
3. https://lore.kernel.org/lkml/20191030120440.3699-1-peter.ujfalusi@ti.com/
4. https://lore.kernel.org/all/20211018234923.1769028-1-sean.anderson@seco.com/
5. https://social.treehouse.systems/@marcan/111268780311634160

I try to solve my case, hopefuly Chris' (2), partially Sean's (4) and maybe
Hectors (5), using Rob's suggestion:

https://lore.kernel.org/all/YXi5CUCEi7YmNxXM@robh.at.kernel.org/

Best regards,
Krzysztof

Cc: Chris Packham <chris.packham@alliedtelesis.co.nz>
Cc: Bartosz Golaszewski <brgl@bgdev.pl>
Cc: Sean Anderson <sean.anderson@seco.com>

Krzysztof Kozlowski (4):
  reset: gpio: Add GPIO-based reset controller
  reset: Instantiate reset GPIO controller for shared reset-gpios
  ASoC: dt-bindings: qcom,wsa8840: Add reset-gpios for shared line
  ASoC: codecs: wsa884x: Allow sharing reset GPIO

 .../bindings/sound/qcom,wsa8840.yaml          |  11 +-
 MAINTAINERS                                   |   5 +
 drivers/reset/Kconfig                         |   9 +
 drivers/reset/Makefile                        |   1 +
 drivers/reset/core.c                          | 176 ++++++++++++++++--
 drivers/reset/reset-gpio.c                    | 121 ++++++++++++
 include/linux/reset-controller.h              |   4 +
 sound/soc/codecs/wsa884x.c                    |  53 +++++-
 8 files changed, 356 insertions(+), 24 deletions(-)
 create mode 100644 drivers/reset/reset-gpio.c